结合低场核磁共振分析反复冻融处理对肉鸡不同部位肌肉品质的影响

Effect of Freeze-Thaw Cycles on the Quality of Broiler Breast and Thigh Muscles as Evaluated by Low-Field Nuclear Magnetic Resonance

利用低场核磁共振(low-field nuclear magnetic resonance,LF-NMR)技术研究反复冻融处理对肉鸡不同部位肌肉品质的影响。结果表明,反复冻融期间p H值变化不显著(P>0.05)。随着冻融次数的增加,肉鸡胸肉和腿肉解冻汁液损失显著下降(P<0.05),硫代巴比妥酸反应物质(thiobabituric acid reactive substance,TBARS)值显著增大,总蛋白溶解度以及肌原纤维小片化冻融初期呈现上升趋势,总水分含量均逐渐降低。低场核磁共振T2弛豫时间分析显示,其自由水占比显著下降(P<0.05)。以上结果说明反复冻融使解冻汁液损失伴随自由水比例显著下降而逐步降低,由于肌肉p H值保持稳定,推测反复冻融过程中反复形成的冰晶对肌肉微观结构的破坏,尤其对肌原纤维蛋白质溶解度的影响起到一定的作用。

In the present study, the effect of freeze-thaw cycles on the quality of broiler breast and thigh muscles was explored by low-field nuclear magnetic resonance（LF-NMR）. Results showed that thaw exudate loss of chicken breast and thigh muscles significantly declined with increasing number of freeze-thaw cycles（P〈0.05）, whereas no significant change in p H was observed（P〈0.05）. The thiobabituric acid reactive substance（TBARS） value of chicken breast and thigh muscles rose significantly, and total protein solubility and myofibrillar fragmentation index（MFI） showed an increasing trend initially. However, total water content gradually fell. At the same time, the proportion of free water as indicated by LF-NMR T2 relaxation times significantly dropped. These above results suggested that freeze-thaw cycles resulted in a reduced proportion of free water and consequently enhanced loss of thaw exudate in chicken muscles. p H maintenance during freezethaw cycles confirmed that ice crystal formation caused damage to the microstructure of muscles, especially having a certain influence on the solubility of myofibrillar protein.